Thysanoessa longipes Brandt, 1851
A Pacific krill expatriated into the Arctic
Size
- Eggs & nauplii 0.35-0.45 mm
- Adults 18-30 mm
Color & Characteristics
- Transparent, yellowish if rich in lipids, females might develop blue hue when spawning
- Eyes bi-lobed, rostrum pointed, photophores red
- Anntennae lack lappet, carapace with denticle
- Abdominal segments 3-6 terminate dorsally with spines
- 6th abdominal segment shorter than the two preceding segments combined
- second pair of thorathic legs elongated, but often broken during collection
Habitat
- Subarctic Pacific in shelf-break habitats deeper than 200 m, amd some some isolated deep fjords
- Transposted into the Chukchi Sea by currents
- Undergo limited diel vertical migrations, spending daytime near bottom or typically 150-300 m (500 m maximum), night-time shallower
Feeding
- Primarily predatory on smaller zooplankton, but can consume algae when abundant
- Prey item for fish, birds, seals and whales
Life cycle
- Females lay several clutches of eggs during spring
- Females require repeated mating after each molt to form new egg clutches
- Life cycles is typcial: eggs, nauplius, metanauplius, followed by several stages of feeding calytopsis, and furcillia larvae
- Juveniles resemble adults, and molt regularly while growing to adulthood over the first year of life
- Life expectancy not known, likely 2-3 years
Page Authors: Alexei Pinchuk & Russ Hopcroft
Created: Sept 3, 2010